Wall shear rate (WSR), a key marker of vascular health, is useful for cardiovascular risk assessment. Traditionally, its non-invasive evaluation via ultrasound relies on longitudinal imaging of the artery, a method that can be restrictive for comprehensive hemodynamic monitoring. Here a bi-plane ultrasound method using a 2D sparse array for fast, cross-sectional WSR estimation is presented. The technique provides 12 simultaneous, angularly distributed WSR estimates per frame, overcoming limitations of conventional methods and avoiding the hardware complexity of full 3D imaging. Phantom experiments were conducted at different depths with good accuracy (bias<16%) and repeatability (<21%).